Spatio-temporal Dynamics Of Priacanthus Spp.resources In The Northern South China Sea Based On Geostatistical Methods

The study on the center of gravity of resource density and its spatial autocorrelation pattern of economic fish is helpful to reveal its habitat distribution characteristics and in-depth understanding of the formation process of its fishing ground,and provide a reference basis for the sustainable utilization and scientific management of its fishery resources.The fishery resources in the northern South China Sea have declined seriously due to long-term overfishing.As an important fishing object of bottom trawling in the northern South China Sea,Priacanthus spp.is under great pressure,so exploring the pattern characteristics of the spatial distribution of Priacanthus spp.resource can improve the accuracy of the resource evaluation.To study this,we used the data of bottom trawl fishery in the northern South China Sea by a fishery information network from 2009 to 2014,for spatial analysis of center of gravity,bootstrap and geostatistical methods to investigate the temporal and spatial dynamics of Priacanthus spp.resource density and its influencing factors.The scientific research work of economic fishes in the South China Sea was supplemented,and the research method of spatial autocorrelation pattern analysis of domestic marine fishery resources was innovated.The main results are described as follows:1)In the survey area,the resource density of Priacanthus spp.is mainly in the low-density area and less in the high-density area,which shows a decreasing trend year by year.The maximum value of resource density appeared in 2012,which was(26.69 ±7.34)g/h/k W/nets,and the minimum value appeared in 2013,which was(8.00 ±0.93)g/h/k W/nets.The resource density of Priacanthus spp.was significantly different in different years(P < 0.01).Long-term overfishing of fishermen leads to the reduction of resources and the miniaturization of fishing population.The change of resource density of Priacanthus spp.may be related to the anomaly of average sea surface salinity.2)The center of gravity of the resource density distributed between the 50-m and 100-m isobath in the middle part of the survey area,and the differences were not significant(P>0.05).The comprehensive effects of dietary and environmental factors such as depth and salinity may lead to the transfer of the center of gravity of Priacanthus spp..3)The spatial distribution of Priacanthus spp.in the survey area displayed a wellorganized structure,with strong spatial autocorrelation in 70–90 km.Spatial heterogeneity in resource density of Priacanthus spp.appeared to be caused less by randomness than by structural variations.The spatial distribution of Priacanthus spp.displayed weak spatial autocorrelation when the distance exceeded 90 km.The types of spatial variation function models are affected by El Nino and La Nina phenomena.The spatial distribution of resource density of Priacanthus spp.is affected by structural and random components,such as environmental conditions and human behavior,which increases or decreases the level of spatial autocorrelation and results in differences in spatio-temporal heterogeneity.The anisotropy of the distribution of Priacanthus spp.is affected by ocean current and fresh water.4)Incremental spatial autocorrelation analysis showed that the resources of Priacanthus spp.had a strong spatial autocorrelation pattern in the scale of 76?87 km,and showed a significant aggregated distribution pattern.5)The hot spot fishing area of Priacanthus spp.is mainly concentrated near the 50?100 m isobath in the middle part of the survey area,and the cold spot fishing area is mainly near the 50-m isobath.The distribution of cold hot spot fishing area in each year corresponds to the species of variation function model in that year.6)The spatial autocorrelation pattern of Priacanthus spp.resources in the northern South China Sea based on incremental spatial autocorrelation analysis has good rationality and accuracy.This study promotes interdisciplinary research,at the same time it provides a new idea for exploring the spatial autocorrelation pattern of marine fishery resources.